School of Biology & Environmental Sciencehttp://hdl.handle.net/10197/3115

2015-03-31T20:51:29ZMechanisms of beneficial colonisation of barley by fungal root endophyteshttp://hdl.handle.net/10197/6169
Mechanisms of beneficial colonisation of barley by fungal root endophytes
Murphy, Brian; Hodkinson, Trevor; Doohan, Fiona
Pathogenic fungal infections of barley can lead to costly crop losses. However, not all
fungal infections are detrimental, and some are even beneficial. Beneficial root infections
often involve symbiotic endophytic fungi. Benefits to barley and other plants infected
with endophytic root fungi include an increase in seed yield, enhanced resistance to
pathogens and improved stress tolerance. Here, we examine the mechanisms and
outcomes of fungal endophyte colonisation of barley roots and briefly discuss reported
benefits for the host. The most important factors that determine the nature of the
relationship are the specific combination of partner genotypes and developmental stage,
and the ecological and environmental setting. The full potential of these organisms is still
to be determined and further studies are urgently required to develop specific beneficial
root-endophyte associations, or combination of them, that are tailored to barley cultivars
for maximum impact in agriculture.
2013-01-01T00:00:00ZLight influences how the fungal toxin deoxynivalenol affects plant cell death and defense responseshttp://hdl.handle.net/10197/6130
Light influences how the fungal toxin deoxynivalenol affects plant cell death and defense responses
Ansari, Khairul I.; Doyle, Siamsa M.; Kacprzyk, Joanna; Arunachalam, Chanemouga Soundharam; McCabe, Paul F.; Doohan, Fiona; et al.
The Fusarium mycotoxin deoxynivalenol (DON) can cause cell death in wheat (Triticum aestivum), but can also reduce the level of cell death caused by heat shock in Arabidopsis (Arabidopsis thaliana) cell cultures. We show that 10 μg mL−1 DON does not cause cell death in Arabidopsis cell cultures, and its ability to retard heat-induced cell death is light dependent. Under dark conditions, it actually promoted heat-induced cell death. Wheat cultivars differ in their ability to resist this toxin, and we investigated if the ability of wheat to mount defense responses was light dependent. We found no evidence that light affected the transcription of defense genes in DON-treated roots of seedlings of two wheat cultivars, namely cultivar CM82036 that is resistant to DON-induced bleaching of spikelet tissue and cultivar Remus that is not. However, DON treatment of roots led to genotype-dependent and light-enhanced defense transcript accumulation in coleoptiles. Wheat transcripts encoding a phenylalanine ammonia lyase (PAL) gene (previously associated with Fusarium resistance), non-expressor of pathogenesis-related genes-1 (NPR1) and a class III plant peroxidase (POX) were DON-upregulated in coleoptiles of wheat cultivar CM82036 but not of cultivar Remus, and DON-upregulation of these transcripts in cultivar CM82036 was light enhanced. Light and genotype-dependent differences in the DON/DON derivative content of coleoptiles were also observed. These results, coupled with previous findings regarding the effect of DON on plants, show that light either directly or indirectly influences the plant defense responses to DON.
2014-02-20T00:00:00ZInsights from the Fungus Fusarium oxysporum Point to High Affinity Glucose Transporters as Targets for Enhancing Ethanol Production from Lignocellulosehttp://hdl.handle.net/10197/6129
Insights from the Fungus Fusarium oxysporum Point to High Affinity Glucose Transporters as Targets for Enhancing Ethanol Production from Lignocellulose
Ali, Shahin S.; Nugent, Brian; Mullins, Ewen; Doohan, Fiona
Ethanol is the most-widely used biofuel in the world today. Lignocellulosic plant biomass derived from agricultural residue can be converted to ethanol via microbial bioprocessing. Fungi such as Fusarium oxysporum can simultaneously saccharify straw to sugars and ferment sugars to ethanol. But there are many bottlenecks that need to be overcome to increase the efficacy of microbial production of ethanol from straw, not least enhancement of the rate of fermentation of both hexose and pentose sugars. This research tested the hypothesis that the rate of sugar uptake by F. oxysporum would enhance the ethanol yields from lignocellulosic straw and that high affinity glucose transporters can enhance ethanol yields from this substrate. We characterized a novel hexose transporter (Hxt) from this fungus. The F. oxysporum Hxt represents a novel transporter with homology to yeast glucose signaling/transporter proteins Rgt2 and Snf3, but it lacks their C-terminal domain which is necessary for glucose signalling. Its expression level decreased with increasing glucose concentration in the medium and in a glucose uptake study the Km(glucose) was 0.9 mM, which indicated that the protein is a high affinity glucose transporter. Post-translational gene silencing or over expression of the Hxt in F. oxysporum directly affected the glucose and xylose transport capacity and ethanol yielded by F. oxysporum from straw, glucose and xylose. Thus we conclude that this Hxt has the capacity to transport both C5 and C6 sugars and to enhance ethanol yields from lignocellulosic material. This study has confirmed that high affinity glucose transporters are ideal candidates for improving ethanol yields from lignocellulose because their activity and level of expression is high in low glucose concentrations, which is very common during the process of consolidated processing.
2013-01-30T00:00:00ZThe Fusarium Mycotoxin Deoxynivalenol Can Inhibit Plant Apoptosis-Like Programmed Cell Deathhttp://hdl.handle.net/10197/6128
The Fusarium Mycotoxin Deoxynivalenol Can Inhibit Plant Apoptosis-Like Programmed Cell Death
Diamond, Mark; Reape, Theresa J.; Rocha, Olga; Doyle, Siamsa M.; Kacprzyk, Joanna; Doohan, Fiona; McCabe, Paul F.
The Fusarium genus of fungi is responsible for commercially devastating crop diseases and the contamination of cereals with harmful mycotoxins. Fusarium mycotoxins aid infection, establishment, and spread of the fungus within the host plant. We investigated the effects of the Fusarium mycotoxin deoxynivalenol (DON) on the viability of Arabidopsis cells. Although it is known to trigger apoptosis in animal cells, DON treatment at low concentrations surprisingly did not kill these cells. On the contrary, we found that DON inhibited apoptosis-like programmed cell death (PCD) in Arabidopsis cells subjected to abiotic stress treatment in a manner independent of mitochondrial cytochrome c release. This suggested that Fusarium may utilise mycotoxins to suppress plant apoptosis-like PCD. To test this, we infected Arabidopsis cells with a wild type and a DON-minus mutant strain of F. graminearum and found that only the DON producing strain could inhibit death induced by heat treatment. These results indicate that mycotoxins may be capable of disarming plant apoptosis-like PCD and thereby suggest a novel way that some fungi can influence plant cell fate.
2013-07-26T00:00:00ZGenome sequence of Ensifer adhaerens OV14 provides insights into its ability as a novel vector for the genetic transformation of plant genomeshttp://hdl.handle.net/10197/6127
Genome sequence of Ensifer adhaerens OV14 provides insights into its ability as a novel vector for the genetic transformation of plant genomes
Rudder, Steven; Doohan, Fiona; Creevey, Christopher J.; Wendt, Toni; et al.
Background: Recently it has been shown that Ensifer adhaerens can be used as a plant transformation technology, transferring genes into several plant genomes when equipped with a Ti plasmid. For this study, we have sequenced the genome of Ensifer adhaerens OV14 (OV14) and compared it with those of Agrobacterium tumefaciens C58 (C58) and Sinorhizobium meliloti 1021 (1021); the latter of which has also demonstrated a capacity to genetically transform crop genomes, albeit at significantly reduced frequencies. Results:
The 7.7 Mb OV14 genome comprises two chromosomes and two plasmids. All protein coding regions in the OV14 genome were functionally grouped based on an eggNOG database. No genes homologous to the A. tumefaciens Ti plasmid vir genes appeared to be present in the OV14 genome. Unexpectedly, OV14 and 1021 were found to possess homologs to chromosomal based genes cited as essential to A. tumefaciens T-DNA transfer. Of significance, genes that are non-essential but exert a positive influence on virulence and the ability to genetically transform host genomes were identified in OV14 but were absent from the 1021 genome. Conclusions: This study reveals the presence of homologs to chromosomally based Agrobacterium genes that support T-DNA transfer within the genome of OV14 and other alphaproteobacteria. The sequencing and analysis of the OV14 genome increases our understanding of T-DNA transfer by non-Agrobacterium species and creates a platform for the continued improvement of Ensifer-mediated transformation (EMT).
2014-04-07T00:00:00ZEstimating body mass in New World "monkeys" (Platyrrhini, Primates), with a consideration of the Miocene platyrrhine, Chilecebus carrascoensishttp://hdl.handle.net/10197/4943
Estimating body mass in New World "monkeys" (Platyrrhini, Primates), with a consideration of the Miocene platyrrhine, Chilecebus carrascoensis
Sears, Karen E.; Finarelli, John A.; Flynn, John J. (John Joseph); Wyss, André R.
Well-constrained estimates of adult body mass for fossil platyrrhine species (New World "monkeys") are essential for resolving numerous paleobiological questions. However, no consensus exists as to which craniodental measures best correlate with body mass among extant taxa in this clade. In this analysis, we analyze 80 craniodental variables and generate predictive equations applicable to fossil taxa, including the early platyrrhine Chilecebus carrascoensis. We find mandibular length to be the best craniodental predictor of body mass. There is no significant difference in predictive value between osteological and dental measures. Variables associated with the mandible and lower dentition do significantly outperform the cranium and upper dentition. Additionally, we demonstrate that modern platyrrhines differ, morphometrically, from early fossil forms. Chilecebus possesses unusual cranial proportions in several key features, as well as proportionally narrow upper incisors and wide upper cheek teeth. These variables yield widely divergent body mass estimates for Chilecebus, implying that the correlations observed in a crown group cannot be assumed a priori for early diverging fossils. Variables allometrically consistent with those in extant forms yield a body mass estimate of slightly less than 600 grams for Chilecebus, nearly a factor of two smaller than prior preliminary estimates. Scaled to body mass, the brain of Chilecebus is markedly smaller than those of modern anthropoids, despite its lowered body mass estimate advocated here. This finding, in conjunction with a similar pattern exhibited by fossil catarrhines, suggests that increased encephalization arose independently in the two extant subgroups of anthropoids (platyrrhines and catarrhines).
2008-01-01T00:00:00ZThe impact of farming on over-wintering bird populationshttp://hdl.handle.net/10197/4518
The impact of farming on over-wintering bird populations
McMahon, Barry J.; Whelan, John; Bracken, Fintan; Kavanagh, Brendan
Field boundaries and fields in stubble, set-aside, winter wheat and improved grassland in County Kildare were surveyed for birds on 15 occasions between October 2001 and February 2002. A total of 40 species was recorded on all sites during the period of the study. Arable farming that retains stubble throughout the winter supports the greatest species richness and diversity with the lowest being recorded on improved grassland. Individual species showed preference for certain sites. Seed-feeding species, yellowhammer and skylark, preferred stubble while invertebrate-feeding species, fieldfare and meadow pipit preferred grassland. The analysis demonstrated that certain components of habitat were responsible for differences in species present and density.
2003-01-01T00:00:00ZInfluence of Surface Groups on Poly(propylene imine) Dendrimers Antiprion Activityhttp://hdl.handle.net/10197/4251
Influence of Surface Groups on Poly(propylene imine) Dendrimers Antiprion Activity
McCarthy, James M.; Moreno, Beatriz Rasines; Filippini, Damien; Komber, Hartmut; Maly, Marek; Cernescu, Michaela; Brutschy, Bernhard; Appelhans, Dietmar; Rogers, Mark S.
Prion diseases are characterized by the accumulation of PrP(Sc), an aberrantly folded isoform of the host protein PrP(C). Specific forms of synthetic molecules known as dendrimers are able to eliminate protease-resistant PrP(Sc) in both an intracellular and in vitro setting. The properties of a dendrimer which govern this ability are unknown. We addressed the issue by comparing the in vitro antiprion ability of numerous modified poly(propylene-imine) dendrimers, which varied in size, structure, charge, and surface group composition. Several of the modified dendrimers, including an anionic glycodendrimer, reduced the level of protease resistant PrP(Sc) in a prion strain-dependent manner. This led to the formulation of a new working model for dendrimer/prion interactions which proposes dendrimers eliminate PrP(Sc) by destabilizing the protein and rendering it susceptible to proteolysis. This ability is not dependent on any particular charge of dendrimer, but does require a high density of reactive surface groups.
2012-12-12T00:00:00ZInfluence of surface functionality of poly(propylene imine) dendrimers on protease resistance and propagation of the scrapie prion proteinhttp://hdl.handle.net/10197/4250
Influence of surface functionality of poly(propylene imine) dendrimers on protease resistance and propagation of the scrapie prion protein
Fischer, Marlies; Appelhans, Dietmar; Schwarz, Simona; Klajnert, Barbara; Bryszewska, Maria; Voit, Brigitte; Rogers, Mark S.
Accumulation of PrP(Sc), an insoluble and protease-resistant pathogenic isoform of the cellular prion protein (PrP(C)), is a hallmark in prion diseases. Branched polyamines, including PPI (poly(propylene imine)) dendrimers, are able to remove protease resistant PrP(Sc) and abolish infectivity, offering possible applications for therapy. These dendrimer types are thought to act through their positively charged amino surface groups. In the present study, the molecular basis of the antiprion activity of dendrimers was further investigated, employing modified PPI dendrimers in which the positively charged amino surface groups were substituted with neutral carbohydrate units of maltose (mPPI) or maltotriose (m3PPI). Modification of surface groups greatly reduced the toxicity associated with unmodified PPI but did not abolish its antiprion activity, suggesting that the presence of cationic surface groups is not essential for dendrimer action. PPI and mPPI dendrimers of generation 5 were equally effective in reducing levels of protease-resistant PrP(Sc) (PrP(res)) in a dose- and time-dependent manner in ScN2a cells and in pre-existing aggregates in homogenates from infected brain. Solubility assays revealed that total levels of PrP(Sc) in scrapie-infected mouse neuroblastoma (ScN2a) cells were reduced by mPPI. Coupled with the known ability of polyamino dendrimers to render protease-resistant PrP(Sc) in pre-existing aggregates of PrP(Sc) susceptible to proteolysis, these findings strongly suggest that within infected cells dendrimers reduce total amounts of PrP(Sc) by mediating its denaturation and subsequent elimination.
2010-04-20T00:00:00ZDifferentiating prion strains using dendrimershttp://hdl.handle.net/10197/4249
Differentiating prion strains using dendrimers
McCarthy, James M.; Rasines, Beatriz; Appelhans, Dietmar; Rogers, Mark S.
A panel of repetitively branched synthetic molecules known as dendrimers is used to identify and differentiate between different strains of the prion infectious agent, the protein-based pathogen responsible for prion disorders—a group of invariably fatal neurodegenerative diseases
2012-11-01T00:00:00ZAnti-prion drug mPPIg5 inhibits PrPC conversion to PrPSchttp://hdl.handle.net/10197/4244
Anti-prion drug mPPIg5 inhibits PrPC conversion to PrPSc
McCarthy, James M.; Franke, Markus; Resenberger, Ulrike K.; Waldron, Sibeal; Simpson, Jeremy C.; Tatzelt, Jörg; Appelhans, Dietmar; Rogers, Mark S.
Prion diseases, also known
as transmissible spongiform encephalopathies, are a group of fatal
neurodegenerative diseases that include scrapie in sheep, bovine spongiform encephalopathy
(BSE) in cattle and Creutzfeldt-Jakob disease (CJD) in humans. The 'protein
only hypothesis' advocates that PrPSc, an abnormal isoform of the
cellular protein PrPC, is the main and possibly sole component of
prion infectious agents. Currently, no effective therapy exists for these
diseases at the symptomatic phase for either humans or animals, though a number
of compounds have demonstrated the ability to eliminate PrPSc in cell culture
models. Of particular interest are synthetic polymers known as dendrimers which
possess the unique ability to eliminate PrPSc in both an
intracellular and in vitro setting. The efficacy and mode of action of
the novel anti-prion dendrimer mPPIg5 was investigated through the creation of
a number of innovative bio-assays based upon the scrapie cell assay. These
assays were used to demonstrate that mPPIg5 is a highly effective anti-prion
drug which acts, at least in part, through the inhibition of PrPC to
PrPSc conversion. Understanding how a drug works is a vital component
in maximising its performance. By establishing the efficacy and method of
action of mPPIg5, this study will help determine which drugs are most likely to
enhance this effect and also aid the design of dendrimers with anti-prion
capabilities for the future.
2013-01-28T00:00:00ZThe impact of a catastrophic storm event on benthic macroinvertebrate communities in upland headwater streams and potential implications for ecological diversity and assessment of ecological statushttp://hdl.handle.net/10197/4221
The impact of a catastrophic storm event on benthic macroinvertebrate communities in upland headwater streams and potential implications for ecological diversity and assessment of ecological status
Feeley, Hugh B.; Davis, Stephen; Bruen, Michael; Blacklocke, Sean; Kelly-Quinn, Mary
Upland headwater streams are dynamic systems, responding rapidly to changes in climatic conditions. This study examined the effects of a catastrophic rainfall event, that occured on 24 October 2011 on the east coast of Ireland, on the macroinvertebrate community composition and structure of four headwater streams in the river Liffey catchment located in the Wicklow Mountains. The ecological status before and after the storm were also evaluated. The water level and pH of each stream were recorded using continuous monitoring equipment, while rainfall data for the study period were sourced from a local weather station. Benthic macroinvertebrates were investigated before and after the storm event using Surber sampling. Results showed rapid and large increases in water level and significant declines in stream pH in response to intensive rainfall during the storm. The high water levels also caused major physical damage and abrasion in all four streams, that significantly altered instream habitats. The storm event induced significant losses to the richness and/or density of most taxonomic groups, with the exception of the Plecoptera. Furthermore, the overall community composition and structure changed significantly, most likely as a result of physical disturbance, given the relative persistence of acid-sensitive taxa and the relatively short period of harsh acidic conditions (<5 pH). Interestingly however, the ecological status of each of the four study sites, tested using Stream Risk Score (SSRS), Biological Monitoring Working Party (BMWP) and the Average Score Per Taxon (ASPT) indices, was unaltered by the loss in richness and densities. This was likely a result of the maintenance of plecopteran richness and the absence of organic pollution, thus highlighting the need to develop appropriate indices to assess the ecological status of streams and rivers affected by physical disturbance caused by large storm events. Ultimately, catastrophic storm events in upland headwater streams have potentially major implications for the maintenance of regional macroinvertebrate diversity within affected regions.
2012-07-24T00:00:00ZAn in vivo root hair assay for determining rates of apoptotic-like programmed cell death in plantshttp://hdl.handle.net/10197/3791
An in vivo root hair assay for determining rates of apoptotic-like programmed cell death in plants
Kacprzyk, Joanna; O'Reilly, Conor; Gallois, Patric; McCabe, Paul F.; Hogg, Bridget V .; Molony, Elizabeth M.; Gallagher, Thomas F.
In Arabidopsis thaliana we demonstrate that dying root hairs provide an easy and rapid in vivo model for the morphological identification of apoptotic-like programmed cell death in plants. The model described here is transferable between the species, can be used to investigate the rates of AL-PCD in response to various treatments and to identify modulation of AL-PCD rates in mutant/transgenic plant lines facilitating rapid screening of mutant populations in order to identify genes involved in AL-PCD regulation
2011-12-13T00:00:00ZThe coupled δ13C-radiocarbon systematics of three late Glacial/early Holocene speleothems; insights into soil and cave processes at climatic transitionshttp://hdl.handle.net/10197/3705
The coupled δ13C-radiocarbon systematics of three late Glacial/early Holocene speleothems; insights into soil and cave processes at climatic transitions
Rudzka, Dominika; McDermott, Frank; Baldini, Lisa M.; Fleitmann, Dominik; Moreno, Ana; Stoll, Heather
The coupled δ13C-radiocarbon systematics of three European stalagmites deposited during the Late Glacial and early Holocene were investigated to understand better how the carbon isotope systematics of speleothems respond to climate transitions. The emphasis is on understanding how speleothems may record climate-driven changes in the proportions of biogenic (soil carbon) and limestone bedrock derived carbon. At two of the three sites, the combined δ13C and 14C data argue against greater inputs of limestone carbon as the sole cause of the observed shift to higher d13C during the cold Younger Dryas. In these stalagmites (GAR-01 from La Garma cave, N. Spain and So-1 from Sofular cave, Turkey), the combined changes in δ13C and initial 14C activities suggest enhanced decomposition of old stored, more recalcitrant, soil carbon at the onset of
the warmer early Holocene. Alternative explanations involving gradual temporal changes between open- and closed-system
behaviour during the Late Glacial are difficult to reconcile with observed changes in speleothem δ13C and the growth rates.
In contrast, a stalagmite from Pindal cave (N. Spain) indicates an abrupt change in carbon inputs linked to local hydrological
and disequilibrium isotope fractionation effects, rather than climate change. For the first time, it is shown that while the initial 14C activities of all three stalagmites broadly follow the contemporaneous atmospheric 14C trends (the Younger Dryas atmospheric 14C anomaly can be clearly discerned), subtle changes in speleothem initial 14C activities are linked to climate-driven changes in soil carbon turnover at a climate transition.
2011-08-01T00:00:00ZSpatio-temporal modeling of TB in cattle herdshttp://hdl.handle.net/10197/3704
Spatio-temporal modeling of TB in cattle herds
Kelly, Gabrielle E.
We examine spatial association of bovine TB in cattle herds using data from Ireland.
Badgers (Meles meles), a protected species under the Wildlife Act 1976 (OAG 2012),
have been implicated in the spread of the disease in cattle. Current disease control policies include reactive culling (in response to TB outbreaks) of badgers in the index and neighbouring farms. Kelly and More (2011) using generalized linear geostatistical models, established that TB clusters in cattle herds and estimated the practical spatial ranges at which this occurs. Here this work is extended by taking into account possible anisotropy. Changes in spatial association over two time periods are also examined. The results have direct implications for establishing scale and direction in reactive culling. They are also
of import regarding the evaluation of vaccines for badgers and cattle.
2012-08-01T00:00:00ZBreeding bird populations of Irish peatlands : capsule peatlands are very important habitats for birds despite low species diversityhttp://hdl.handle.net/10197/3620
Breeding bird populations of Irish peatlands : capsule peatlands are very important habitats for birds despite low species diversity
Bracken, Fintan; McMahon, Barry J.; Whelan, John
Aims to describe the variation in breeding bird populations that occur on different types of Irish peatlands and their associated habitat characteristics.
Methods: Bird abundance and diversity were compared between four peatland habitat types: fens; raised bogs; Atlantic blanket bogs; and montane blanket bogs at twelve study sites using transects. Various measures of habitat quality were also taken at each location.
Results: Only 21 species were recorded during the study with Meadow Pipit Anthus pratensis and Sky Lark Alauda arvensis accounting for over 80% of all birds recorded. Fens had greater bird species diversity and densities than the other three peatland types. Raised bogs, Atlantic blanket bogs and montane blanket bogs were very similar in terms of their avian diversity. Each of the recorded bird species were associated with different aspects of the peatland habitat.
Conclusion: This study shows that despite the relatively low avian species diversity of Irish peatlands, they are of enormous conservation value due to the presence of species of high conservation concern such as Red Grouse (Willow Ptarmigan) Lagopus lagopus and Eurasian Curlew Numenius arquata.
2008-01-01T00:00:00ZEffects of set-aside management on birds breeding in lowland Irelandhttp://hdl.handle.net/10197/3619
Effects of set-aside management on birds breeding in lowland Ireland
Bracken, Fintan; Bolger, Thomas
Farmland birds have suffered a severe decline in recent years throughout Europe including Ireland. Agricultural intensification is believed to be the main cause and this has led to the introduction of agri-environmental schemes, of which set-aside is a part. Bird abundance and diversity were compared between set-aside and adjacent tillage or grassland at 18 locations. The set-aside sites were also assigned to one of four management types: rotational set-aside, non-rotational set-aside, first year set-aside that was productive grassland in the previous year, and long-term set-aside that was grazed by animals in winter. Species diversity and the abundances of skylark, meadow pipit and woodpigeon were significantly greater in set-aside sites. Species diversity was not significantly different between set-aside management types and meadow pipit, skylark, pheasant, house sparrow, magpie, snipe and starling were closely associated with non-rotational set-aside, which also contained significantly larger numbers of these species compared to the other set-aside types. This study shows that set-aside does enhance bird diversity and abundance and that, in Ireland, the most effective form of set-aside is non-rotational. It also shows that the most appropriate form of set-aside will vary from situation to situation and that a one size fits all view should not be taken in the development of agri-environmental schemes.
2006-11-01T00:00:00ZThe botanical dance of death : programmed cell death in plantshttp://hdl.handle.net/10197/3454
The botanical dance of death : programmed cell death in plants
Kacprzyk, Joanna; Daly, Cara T.; McCabe, Paul F.
Programmed cell death (PCD) describes a small number of processes that result in a highly controlled, and organised, form of cellular destruction, activated in every part of the plant, throughout its entire life cycle. For example, PCD is a critical component of many vegetative and reproductive developmental processes, senescence programmes, pathogen defence mechanisms and stress responses. Cell destruction can manifest as apoptotic-like, necrotic or autophagic cell death and these processes are likely to overlap extensively, sharing several regulatory mechanisms. Several of the key PCD regulators and signals have now been revealed, for example, many cell organelles, including mitochondria, chloroplasts, Golgi apparatus, endoplasmic reticulum and vacuoles have been shown to have a role in controlling PCD activation. Following activation the actual dismantling of the cell appears to involve cell death proteases including those with caspase-like, or metacaspase, activity. This review will examine the current state of knowledge about the regulation of events during plant PCD. We will describe numerous examples of developmental or environmentally-induced deaths and outline their potential as models systems for use in PCD research programmes. Similarly, a range of techniques and in vitro model systems and that can be used to identify, and quantify, rates of plant PCD are reviewed. These model systems and techniques can be used to identify the underlying signals and events that drive and regulate PCD and ultimately reveal the steps necessary for the botanical dance of death.
2011-10-01T00:00:00Z